DOCSLIB.ORG

I: Normal Subjects

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
I: Normal Subjects British Heart Journal, I972, 34, 874-88I. Br Heart J: first published as 10.1136/hrt.34.9.874 on 1 September 1972. Downloaded from Duration of phases of left ventricular systole using indirect methods I: Normal subjects J. Fabian,' E. J. Epstein, and N. Coulshed From the Liverpool Regional Cardiac Centre, Sefton General Hospital, Liverpool The duration of the various phases of left ventricular systole has been measured in a series of So normal subjects using high speed simultaneous recordings of the electrocardiogram, the phono- cardiogram, the carotid pulse, and the apex cardiogram. The five phases of systole measured were: total electromechanical systole (Q-A2 interval); left ventricular ejection time (LVET); pre-ejection period (PEP); isovolumetric contraction time (IVCT); total mechanical systole (TMS). The Q-A2 interval, left ventricular ejection time, and total mechanical systole were linearly and inversely related to heart rate. The pre-ejection period and the isovolumetric contraction time were not significantly related to heart rate. The validity of the method has been substantiated by comparing simultaneous records ofdirect and indirect pulseforms in a small series ofpatients. The are and at heart rates showed no deviation findings reproducible serial daily studies different from copyright. the normal range. The results have been compared with those reported by various authors and they are in close agreement. Methods used to assess cardiac function, 2) Left ventricular ejection time (LVET). which depend on measurements ofintravascu- 3) Pre-ejection period (PEP). http://heart.bmj.com/ lar pressure and flow, are not readily per- 4) Isovolumetric contraction time (IVCT). formed in ambulant patients. The procedures 5) Total mechanical systole (TMS). are uncomfortable, carry some risk to the patient, and are not easily repeated. The results in normal subjects are presented The duration of the phases of left ventricu- to establish a normal range for comparison lar systole, which are potentially useful as with those in various cardiac disorders. In indices of left ventricular performance, can be addition, we have compared our findings with measured from accurately externally recorded those of other workers. on September 29, 2021 by guest. Protected pulse waves, and such externally recorded time intervals do not appear to differ signifi- cantly from those obtained by direct measure- Methods and subjects ment. Recent publications have described the Studies were performed on 5o normal healthy various techniques which can be used (Jezek, adults (35 men and I5 women) aged i8 tO 79 I963; Oreshkov, I965; Weissler, Harris, and years. Twenty-five were under 40 and 25 were Schoenfeld, i968; Spodick and over 40 years of age. The majority were members Kumar, of the hospital staff and the remainder were sur- i968a and b). gical patients admitted for relatively minor pro- This paper describes a method of recording cedures unrelated to the cardiovascular system. and measuring five important phases of left All subjects had a normal exercise tolerance, no ventricular systole, viz: cardiovascular abnormality on clinical examina- tion, a normal electrocardiogram, and were not i) The Q-A2 interval or total electromechani- on any form of medication. cal systole (TEMS). Simultaneous recordings were made of the electrocardiogram, the phonocardiogram, the Received 28 October 1971. apex cardiogram, and the right carotid arterial 'Present address: First Medical Clinic, Charles Uni- pulse using a multichannel oscilloscopic recorder versity, Vlasska 36, Prague x, Czechoslovakia. (Cambridge Instrument Company) and a paper Duration ofphases of left ventricular systole using indirect methods 875 Br Heart J: first published as 10.1136/hrt.34.9.874 on 1 September 1972. Downloaded from i) The total period of electromechanical systole or the Q-A2 interval. Defined as the interval from the onset of the Q wave of the electrocardiogram 2-e L to the onset ofthe first high frequency component of the aortic component of the second sound. 2) The left ventricular ejection time measured from the beginning of the carotid upstroke to the nadir of the carotid incisura. 3) The interval from the beginning of the up- stroke of the apex cardiogram to the onset of the carotid upstroke. 4) The delay in transmission ofthe central arterial pulse to the carotid artery, or the pulse trans- mission time, measured from the first rapid vibration of the aortic component of the second sound to the nadir of the carotid incisura. ;ii All intervals were calculated as the mean of I1 ( measurements made on at least five cardiac cycles, each read to the nearest 5 msec. Heart rate was ,FIG. i Normal subject: simultaneous records calculated from the average RR interval of the of the apex cardiogram (ACG), the carotid cycles measured. pulse (CP), the phonocardiogram (PCG), and The following intervals were calculated from lead II of the electrocardiogram. A = Q-A2 the above measurements. interval; B = left ventricular ejection time i) Pre-ejection period This was calculated (LVET); C= onset of ACG upstroke (u) to by subtracting the left ventricular ejection time onset of CP upstroke (u); D = A2 to dicrotic from the total period of electromechanical systole notch interval or pulse transmission time (Q-A2 interval). PEP = (Q-A2)- (LVET). This (PTT); E= total mechanical systole (TMS); is the same as the interval from the onset of the copyright. A minus B =pre-ejection period (PEP); Q wave of the electrocardiogram to the onset C minus D = isovolumetric contraction time of the carotid upstroke corrected for the pulse transmission (IVCT); S1=first heart sound; A2, P2 = delay. aortic and pulmonary components of the second 2) Isovolumetric contraction time (IVCT) heart sound; 2L = second left intercostal space The interval from the beginning of the upstroke parasternally; MF= medium frequency. Time of the apex cardiogram (ACGu) to that of the are at msec klines 40 intervals. carotid pulse (CARu) corrected for the delay in http://heart.bmj.com/ transmission of the central arterial pulse to the carotid artery (PTT) (Oreshkov, I965; Spodick and Kumar, i968a). IVCT=ACGu to CARu- speed of IOO mm/sec (Fig. I). The recordings PTT. were performed in a similar fashion to the routine phonocardiographic practice of this Unit (Coul- 3) Total mechanical systole (TMS) The shed and Epstein, I963). Usually standard lead II sum of isovolumetric contraction time (IVCT) of the electrocardiogram was employed. A crystal and left ventricular ejection time (LVET). microphone to record the heart sounds was placed TMS=IVCT+LVET. This is the same as the parasternally in the second or third left interspace. interval from the beginning of the upstroke of the on September 29, 2021 by guest. Protected Occasionally two microphones were used in order apex cardiogram to the aortic component of the to identify the aortic and pulmonary components second heart sound (A2). of the second sound. The right carotid arterial The results on the 50 subjects were statistically pulse and apex cardiogram were recorded using evaluated (Croxton, 1959). Standard deviations funnel-shaped pick-ups with an internal diameter and regression equations were calculated to relate ofapproximately I *5 cm. The funnels were connec- heart rate to systolic time intervals. ted to identical piezoelectric crystal microphones In ii patients with various cardiac disorders a %by similar lengths of rigid plastic tubing less than Telco micromanometer was placed in the central 2 feet in length. There was no time lag between aorta and left ventricle during a diagnostic study. the two recording systems. Records were taken Simultaneous records were made of the carotid with the breath held in partial expiration and with pulse and the central aortic pressure curve in 7 the patient in a semi-left lateral position, in order patients and of the apex cardiogram and the left to bring the apex impulse against the chest wall. ventricular pressure curve in 7 patients. Three of Identification of the underlying zone of the ven- these patients had both aortic and then left ven- tricle was accomplished by recording a unipolar tricular pressures recorded with the carotid pulse -electrocardiogram lead at the site of the apex and the apex cardiogram, respectively. Experi- cardiogram. mental studies showed that there was no signifi- The following intervals were measured directly cant time lag between the Telco micromanometer from the tracing (Fig. i). and the external pulse microphone. 876 Fabian, Epstein, and Coulshed Br Heart J: first published as 10.1136/hrt.34.9.874 on 1 September 1972. Downloaded from Results electrocardiogram, the phonocardiogram, the These are shown in Table and Fig. 2. carotid pulse, and the apex cardiogram. With a fast recording speed of IOO mm/sec, mea- i) Q-A2 interval or total electro- surements can be made within an accuracy of mechanical systole (TEMS) The mean about 5 msec. Braunwald, Sarnoff, and Stainsby (I958) Q-A2 interval was 382 ± 23 msec with a range of 330 to 440 msec. There was a close linear studied left ventricular ejection time in an iso- relation between the Q-A2 interval and heart lated dog heart preparation. They found that rate (Fig. 2). The regression equation was increasing the stroke volume at a fixed heart rate increased the ejection time, whereas in- Y= + 503-I *59 HR (r= -0 79; P < OOOI). creasing the heart rate with a fixed stroke 2) Left ventricular ejection time (LVET) volume shortened the ejection time. Wallace The mean LVET was 28I ±2I msec with a et al. (I963) studied in more detail the various range of 230 tO 334 msec. There was a close phases ofleft ventricular systole in dogs. They linear relation between the LVET and heart showed that increasing the stroke volume at rate (Fig. 2). The regression equation was a fixed heart rate prolonged the ejection time, Y = + 389-I14I HR (r = -078; P <oooi). shortened isovolumetric contraction time, and had little effect on total systole.
Load more

Recommended publications
  • Chapter 20 *Lecture Powerpoint the Circulatory System: Blood Vessels and Circulation
    Chapter 20 *Lecture PowerPoint The Circulatory System: Blood Vessels and Circulation *See separate FlexArt PowerPoint slides for all figures and tables preinserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Introduction • The route taken by the blood after it leaves the heart was a point of much confusion for many centuries – Chinese emperor Huang Ti (2697–2597 BC) believed that blood flowed in a complete circuit around the body and back to the heart – Roman physician Galen (129–c. 199) thought blood flowed back and forth like air; the liver created blood out of nutrients and organs consumed it – English physician William Harvey (1578–1657) did experimentation on circulation in snakes; birth of experimental physiology – After microscope was invented, blood and capillaries were discovered by van Leeuwenhoek and Malpighi 20-2 General Anatomy of the Blood Vessels • Expected Learning Outcomes – Describe the structure of a blood vessel. – Describe the different types of arteries, capillaries, and veins. – Trace the general route usually taken by the blood from the heart and back again. – Describe some variations on this route. 20-3 General Anatomy of the Blood Vessels Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillaries Artery: Tunica interna Tunica media Tunica externa Nerve Vein Figure 20.1a (a) 1 mm © The McGraw-Hill Companies, Inc./Dennis Strete, photographer • Arteries carry blood away from heart • Veins
    [Show full text]
  • Blood Vessels: Part A
    Chapter 19 The Cardiovascular System: Blood Vessels: Part A Blood Vessels • Delivery system of dynamic structures that begins and ends at heart – Arteries: carry blood away from heart; oxygenated except for pulmonary circulation and umbilical vessels of fetus – Capillaries: contact tissue cells; directly serve cellular needs – Veins: carry blood toward heart Structure of Blood Vessel Walls • Lumen – Central blood-containing space • Three wall layers in arteries and veins – Tunica intima, tunica media, and tunica externa • Capillaries – Endothelium with sparse basal lamina Tunics • Tunica intima – Endothelium lines lumen of all vessels • Continuous with endocardium • Slick surface reduces friction – Subendothelial layer in vessels larger than 1 mm; connective tissue basement membrane Tunics • Tunica media – Smooth muscle and sheets of elastin – Sympathetic vasomotor nerve fibers control vasoconstriction and vasodilation of vessels • Influence blood flow and blood pressure Tunics • Tunica externa (tunica adventitia) – Collagen fibers protect and reinforce; anchor to surrounding structures – Contains nerve fibers, lymphatic vessels – Vasa vasorum of larger vessels nourishes external layer Blood Vessels • Vessels vary in length, diameter, wall thickness, tissue makeup • See figure 19.2 for interaction with lymphatic vessels Arterial System: Elastic Arteries • Large thick-walled arteries with elastin in all three tunics • Aorta and its major branches • Large lumen offers low resistance • Inactive in vasoconstriction • Act as pressure reservoirs—expand
    [Show full text]
  • Your Pulse and Target Heart Rate
    Skip to main content ×Close Menu We use cookies to improve your experience on our website. By closing this banner or interacting with our site, you acknowledge and agree to this. Legal Notices MobileClose Menu Find A Doctor Your Visit Pay a Bill Log in to MyGillette Learn more about MyGillette Patient Education Patient Services and Resources Your Rights and Medical Records Understanding Costs, Insurance and the Gillette Assistance Programs Services to Support Your Family Interpreter Services International Patients Parent Resources and Support Prepare for Your Visit Prepare for Clinic Visits and Tests Prepare for Surgery Take a Hospital Tour Transfer Your Medical Records Transportation and Accommodations Ways to Prepare and Comfort Your Child During Your Visit or Hospital Stay Commitment to a Safe and Healing Environment Our Hospital Units Your Hospital Room St. Paul Campus Amenities and Activities Visit or Contact a Patient Conditions & Care All Conditions Cerebral Palsy Neuromuscular Disorders Scoliosis Craniosynostosis Brain Injury All Tests & Treatments Shunt Surgery for Hydrocephalus Gait and Motion Analysis Selective Dorsal Rhizotomy (SDR) Gillette Craniocap© Orthosis Botulinum Toxin and Phenol (Injected Spasticity Medications) All Specialties & Services Orthopedics Rehabilitation Services Craniofacial and Plastic Surgery Neurology Neurosurgery Virtual Visits Pediatric Expert Consults Virtual Rehab Therapy Sleep Medicine Virtual Care Get Involved Advocating for Your Family Community Health United Cerebral Palsy of MN Donors & Supporters
    [Show full text]
  • The Heart Institute
    The Heart Institute Division of Cardiology 4650 Sunset Blvd., #34, Los Angeles, CA 90027 Phone: 323-361-2461 Fax: 323-361-1513 The Heart Institute at Children’s Hospital Los Angeles is CHLA.org/CARDIOLOGY one of the top-ranked pediatric heart programs in the Division of nation—with a long history of exceptional and innovative Cardiothoracic Surgery 4650 Sunset Blvd., #66 care for the most complex pediatric cardiac conditions. Los Angeles, CA 90027 Phone: 323-361-4148 Fax: 323-361-3668 We treat patients from fetus to adulthood and serve as CHLA.org/CTSurgery a major tertiary referral center for all forms of congenital Referrals Phone: 888-631-2452 and acquired heart disease. Fax: 323-361-8988 Email: [email protected] Physician Portal: https://myCHLA.CHLA.org We offer an integrated inpatient and outpatient Our Cardiothoracic Intensive Care Unit (CTICU) complement of services that brings together experts was the first of its kind on the West Coast, using in cardiology, cardiothoracic surgery, cardiothoracic innovative treatments including extracorporeal transplant, cardiothoracic intensive care and membrane oxygenation (ECMO) and ventricular cardiovascular acute care in a centrally located, assist services. state-of-the-art healing environment. With fewer steps to navigate, our patients and families receive care Our two state-of-the-art catheterization laboratories that is more streamlined and less stressful. use the latest technology to provide accurate cardiac data while reducing radiation. Our programmatic emphasis on high-complexity surgeries in neonates has produced outcomes that are among the best in the country, as shown in the most recent Society of Thoracic Surgeons report.
    [Show full text]
  • Bio 104 Cardiovascular System
    29 Bio 104 Cardiovascular System Lecture Outline: Cardiovascular System Hole’s HAP [Chapters 14, 15, 16] Blood: Introduction (Chapter 14) - - - - A. Characteristics of Blood 1. Blood Volume - - - 2. Blood Composition a. Blood Cells Red blood cells White blood cells Platelets b. Plasma 3. Origin of Blood Cells - - 30 Bio 104 Cardiovascular System B. Red Blood Cells 1. Characteristics - - - oxyhemoglobin - deoxyhemoglobin - 2. Red Blood Cell Counts 4.6 – 6.2 4.2. – 5.4 reflects blood’s ___________________________ 3. Red Blood Cell Production low blood oxygen ________________________ RBC production vitamin B12, folic acid, Fe are necessary Dietary Factors Affecting RBC Production 31 Bio 104 Cardiovascular System 4. Life Cycle of RBC lifespan worn out RBCs destroyed by Hb heme and globin 5. Anemia Def. = C. White Blood Cells 1. Functions & Types diapedesis positive chemotaxis granulocytes - - - agranulocytes - - 32 Bio 104 Cardiovascular System 2. White Blood Cell Counts 5, 000 - 10,000 leukopenia leukocytosis differential WBC count Granulocytes Agranulocytes Neutrophils (segs, PMNs, bands) Monocytes Eosinophils Lymphocytes Basophils D. Platelets - cell fragments -130,000 - 360,000 - helps control _______________ Plasma A. Characteristics 33 Bio 104 Cardiovascular System B. Plasma Proteins C. Gases and Nutrients Gases Nutrients - - - - - - D. Nonprotein Nitrogenous Substances Urea - Uric acid - Amino acids – Creatine – Creatinine – BUN – E. Plasma Electrolytes Absorbed from the _____________ or released as by-products
    [Show full text]
  • Effects of Vasodilation and Arterial Resistance on Cardiac Output Aliya Siddiqui Department of Biotechnology, Chaitanya P.G
    & Experim l e ca n i t in a l l C Aliya, J Clinic Experiment Cardiol 2011, 2:11 C f a Journal of Clinical & Experimental o r d l DOI: 10.4172/2155-9880.1000170 i a o n l o r g u y o J Cardiology ISSN: 2155-9880 Review Article Open Access Effects of Vasodilation and Arterial Resistance on Cardiac Output Aliya Siddiqui Department of Biotechnology, Chaitanya P.G. College, Kakatiya University, Warangal, India Abstract Heart is one of the most important organs present in human body which pumps blood throughout the body using blood vessels. With each heartbeat, blood is sent throughout the body, carrying oxygen and nutrients to all the cells in body. The cardiac cycle is the sequence of events that occurs when the heart beats. Blood pressure is maximum during systole, when the heart is pushing and minimum during diastole, when the heart is relaxed. Vasodilation caused by relaxation of smooth muscle cells in arteries causes an increase in blood flow. When blood vessels dilate, the blood flow is increased due to a decrease in vascular resistance. Therefore, dilation of arteries and arterioles leads to an immediate decrease in arterial blood pressure and heart rate. Cardiac output is the amount of blood ejected by the left ventricle in one minute. Cardiac output (CO) is the volume of blood being pumped by the heart, by left ventricle in the time interval of one minute. The effects of vasodilation, how the blood quantity increases and decreases along with the blood flow and the arterial blood flow and resistance on cardiac output is discussed in this reviewArticle.
    [Show full text]
  • Heart Failure
    FACT SHEET FOR PATIENTS AND FAMILIES Heart Failure What is it? Enlarged heart Heart failure is a condition in which your heart can’t pump enough blood to meet your body’s needs. Usually, this is because your heart muscle is too weak to “squeeze” out enough blood with each beat. But heart failure can also happen when your heart gets stiff “Normal” heart and can’t fill up with enough blood between each beat. Heart failure is found most often in older people, but it can happen to anyone at any age. It’s a serious condition — and also quite common. Many people with heart failure continue to have a full and active life for many years after their diagnosis. What are the symptoms? Symptoms of heart failure vary based on the type of With heart failure, initial damage weakens the heart failure you have. Common symptoms include: heart muscle. This makes your heart beat faster, and the muscle stretches or thickens. Over time, • Shortness of breath the heart muscle begins to wear out. • Cough • Feeling very tired and weak • Atherosclerosis (coronary artery disease). • Weight gain (from fluid buildup) Atherosclerosis is when the arteries that supply your • Swollen ankles, feet, belly, lower back, and fingers heart with blood become narrowed by fatty plaque • Puffiness or swelling around the eyes buildup. This restricts the amount of oxygen your • Trouble concentrating or remembering heart gets and weakens the muscle. It can also cause a heart attack, which can damage your heart even more. The main cause of heart failure (heart muscle damage and weakness) cannot be cured, but symptoms can be • High blood pressure (hypertension).
    [Show full text]
  • Time-Varying Elastance and Left Ventricular Aortic Coupling Keith R
    Walley Critical Care (2016) 20:270 DOI 10.1186/s13054-016-1439-6 REVIEW Open Access Left ventricular function: time-varying elastance and left ventricular aortic coupling Keith R. Walley Abstract heart must have special characteristics that allow it to respond appropriately and deliver necessary blood flow Many aspects of left ventricular function are explained and oxygen, even though flow is regulated from outside by considering ventricular pressure–volume characteristics. the heart. Contractility is best measured by the slope, Emax, of the To understand these special cardiac characteristics we end-systolic pressure–volume relationship. Ventricular start with ventricular function curves and show how systole is usefully characterized by a time-varying these curves are generated by underlying ventricular elastance (ΔP/ΔV). An extended area, the pressure– pressure–volume characteristics. Understanding ventricu- volume area, subtended by the ventricular pressure– lar function from a pressure–volume perspective leads to volume loop (useful mechanical work) and the ESPVR consideration of concepts such as time-varying ventricular (energy expended without mechanical work), is linearly elastance and the connection between the work of the related to myocardial oxygen consumption per beat. heart during a cardiac cycle and myocardial oxygen con- For energetically efficient systolic ejection ventricular sumption. Connection of the heart to the arterial circula- elastance should be, and is, matched to aortic elastance. tion is then considered. Diastole and the connection of Without matching, the fraction of energy expended the heart to the venous circulation is considered in an ab- without mechanical work increases and energy is lost breviated form as these relationships, which define how during ejection across the aortic valve.
    [Show full text]
  • CARDIAC CYCLE & CONTROL (All Cd References Refer to Interactiv
    Biology 251 Fall 2015 TOPIC 15: CARDIOVASCULAR SYSTEM: CARDIAC CYCLE & CONTROL (All cd references refer to Interactive Physiology cd, Cardiovascular menu) I. Mechanical Events in the Cardiac Cycle (Figs 13.18 to 13.21; cd cardiac cycle 5 to 17) A. Introduction 1. Systole: Contraction and emptying of the chambers 2. Diastole: Relaxation and filling of the chambers 3. Atria and Ventricles go through separate cycles of systole and diastole 4. The contraction status (being in systole or diastole) determines heart chamber pressure which determines whether valves are open or closed. B. TP interval: Ventricular diastole 1. Atria and ventricles are in diastole (i.e., relaxed). 2. Blood flows from veins into atria 3. Ventricuclar Pressure < Aortic Pressure = Aortic Valve closed 4. Atrial pressure > Ventricular Pressure = AV valve open so 5. Blood flows from atria directly into ventricles. C. P wave and PQ interval: Late ventricular diastole 1. Ventricuclar Pressure < Aortic Pressure = aortic valve closed 2. SA node reaches threshold and fires. 3. Atrial depolarization occurs. 4. Atria contract = atrial systole 5. Atrial Pressure > Ventricular Pressure = AV valves open. 6. Blood squeezed by atrial contraction from atria into ventricles. D. QR Interval: End of ventricular diastole 1. Ventricuclar pressure < Aortic Pressure = Aortic Valve closed 2. Atrial Pressure > Ventricular Pressure = AV valves open. 3. Blood squeezed from atria into ventricles. 4. Electrical impulse enters ventricles from the AV node. 5. Ventricles begin to depolarize. 6. R peak is end of ventricular diastole and start of ventricular systole. E. RS interval: Early ventricluar systole 1. Ventricles begin to contract. 2. Atrial Pressure < Ventricle Pressure = AV valves close 3.
    [Show full text]
  • 04. the Cardiac Cycle/Wiggers Diagram
    Part I Anaesthesia Refresher Course – 2018 4 University of Cape Town The Cardiac Cycle The “Wiggers diagram” Prof. Justiaan Swanevelder Dept of Anaesthesia & Perioperative Medicine University of Cape Town Each cardiac cycle consists of a period of relaxation (diastole) followed by ventricular contraction (systole). During diastole the ventricles are relaxed to allow filling. In systole the right and left ventricles contract, ejecting blood into the pulmonary and systemic circulations respectively. Ventricles The left ventricle pumps blood into the systemic circulation via the aorta. The systemic vascular resistance (SVR) is 5–7 times greater than the pulmonary vascular resistance (PVR). This makes it a high-pressure system (compared with the pulmonary vascular system), which requires a greater mechanical power output from the left ventricle (LV). The free wall of the LV and the interventricular septum form the bulk of the muscle mass in the heart. A normal LV can develop intraventricular pressures up to 300 mmHg. Coronary perfusion to the LV occurs mainly in diastole, when the myocardium is relaxed. The right ventricle receives blood from the venae cavae and coronary circulation, and pumps it via the pulmonary vasculature into the LV. Since PVR is a fraction of SVR, pulmonary arterial pressures are relatively low and the wall thickness of the right ventricle (RV) is much less than that of the LV. The RV thus resembles a passive conduit rather than a pump. Coronary perfusion to the RV occurs continuously during systole and diastole because of the low intraventricular and intramural pressures. In spite of the anatomical differences, the mechanical behaviour of the RV and LV is very similar.
    [Show full text]
  • The Duration of Left Ventricular Systole in Mitral Incompetence
    Br Heart J: first published as 10.1136/hrt.24.4.464 on 1 July 1962. Downloaded from THE DURATION OF LEFT VENTRICULAR SYSTOLE IN MITRAL INCOMPETENCE BY P. G. F. NIXON AND G. R. WAGNER From the Department of Medicine and Thoracic Surgery, in the General Infirmary at Leeds Received December 11, 1961 In mitral incompetence the left ventricle has two exits and it has been suggested that diminished resistance to emptying causes left ventricular systole to be shorter than normal (Brigden and Leatham, 1953). Theoretically the elevation of left ventricular end-diastolic pressure that is found in severe mitral incompetence (Ross et al., 1958; Nixon, 1961a) should result in prolongation of systole. The purpose of this communication is to report measurements of left ventricular systole in patients with mitral incompetence, and to consider their significance. MATERIAL AND METHODS Patients with chronic rheumatic mitral valvular disease submitted to diagnostic left heart catheteri- zation were selected for this study provided they were free from evidence of congestive heart failure, aortic valvular, hypertensive, or ischaemic heart disease: six had atrial fibrillation and were severely http://heart.bmj.com/ disabled by their mitral disease. During cardiac catheterization mean arterial blood pressure lay between 80 and 100 mm. Hg in five cases; in one it was 110 mm. Hg. Pulmonary hyper- tension was present, average pulmonary arterial systolic pressures lying between 40 and 60 mm. Hg. The diagnosis of pure or predominant incompetence was made from the presence of all ofthe follow- ing findings: clinical and radiological evidence of left ventricular enlargement; left ventricular apical impulse displacement curves (Schneider and Klunhaar, 1961) showing a prominent "third heart sound wave ", and evidence ofventricular stasis in diastole (Fig.
    [Show full text]
  • Grade 6: the Heart and Circulatory System Lesson 1: the Heart Lesson 2: the Heart Rate Lesson 3: the Circulatory System and Blood
    Grade 6: The Heart and Circulatory System Lesson 1: The Heart Lesson 2: The Heart Rate Lesson 3: The Circulatory System and Blood Objectives: 1. Students will identify the four chambers of the heart 2. Students will identify four important structures of the Circulatory System and what they do. 3. Students will explain heart rate and be able to take their resting and active heart rates. 4. Students will describe the major functions of the Circulatory System. 5. Students will explain the role of the heart in circulation 6. Students will give a basic explanation of the cardio-pulmonary sequence. 7. Students will describe systemic circulation. Materials: Lesson 1: • Animal heart (Example: cow, pig, sheep) • Note cards • Picture of the heart (See Figure 1) • Dissection tools (Scissors, pan, etc.) Lesson 2: • Small drum • Watch or clock with second hand, or time • Optional: Stethoscope Lesson 3: • Corn Syrup • Plastic Beads: flat red disks, white ovals, green or blue seed beads • “Explain” experiment (per group): o Two small balloons or large finger cots o One clear tube (1/2” diameter) about 8” long o One clear tube (3/4” diameter) about 8” long o 16 - 20 oz. water o Red food coloring o Measuring cup o Funnel o Two empty plastic containers (such as cottage cheese or yogurt cartons) Activity Summary: In this lesson students will learn the basic functioning of the heart, Circulatory System and blood, the connection to lung functioning, and the activity of the Grade 6: The Heart & Circulatory System – Revised 2008 Page 1 Circulatory System in the body.
    [Show full text]